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Fish and Fisheries in Vembanad Lake Consolidated report of Vembanad Fish count 2008- 2011

Krishna Kumar K and Priyadarsanan Dharma Rajan

Community Environment Resource Centre (CERC) Ashoka Trust for Research in Ecology and the Environment (ATREE),

Ammankovil Street, Mullakkal Alappuzha

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Fish and Fisheries in Vembanad Lake Consolidated report of Vembanad fish count 2008- 2011 Authors Krishnakumar K , Research Associate, CERC, ATREE Dr.Priyadarsanan Dharma Rajan, Senior Fellow & Program Leader, , ATREE CERC, Mullakkal, Amman Kovil Street, Alleppey, Kerala Email- vembanad @atree.org www.vembanad.org www.atree.org Lay out & design –Krishnakumar K Cover page pictures – Shaji Cherthala, First prize winning Photograph in Athijeevanam (Photo Competion Organized by ATREE in 2010). Back cover Picture- Krishnakumar K, Fish sanctuary at Vembanad Lake . First published –May 2012 Published by CERC, Ashoka Trust for Research in Ecology and the Environment (ATREE)

Fish and Fisheries in Vembanad Lake Consolidated report of Vembanad fish count 2008- 2011 by Krishna Kumar K & Priyadarsanan Dharma Rajan is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License.

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Contents

Acknowledgements 4

CERC Team 5

Forword 6

Executive Summary 7

Chapter 1 9

Introduction 9

Vembanad Fish count 11

Objectives 13

Methodology 13

Chapter 2 15

Physiochemical Environment 15

Microbial Pollutants 19

Chapter 3 21

Vembanad fish count 2008-2011 21

Fish fauna of Vembanad Lake 25

Changes in fish Fauna of Vembanad 26

Chapter 4 30

Threats to fishes of vembanad lake 30

Changes in Waterscape & Habitat Alteration 30

Over Exploitation and Unsustainable Fishing Practices 33

Pollution 34

Exotic fishes 35

Chapter 5 36

Conservation Interventions 36

Suggestions for Conservation of Vembanad Lake & Fishery Resources 39

References 40

Annexure 42

Check list of Fishes of VFC 2008- 2011

with a Note on its Geographical Distribution

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Acknowledgements We wish to place on record the genuine efforts of many people who made this event a great success in last four years. As joint organizer of this program since its inception we acknowledge the genuine efforts of Dr. K.G. Padma Kumar, Associate Professor of RARS, Kumarakom, for helping us in developing the method for the fishcount and for providing facilities at RARS for the Vemaband fishcoun;, Kerala State Biodiversity Board(SBB) and its Hon. Chairmen of SBB Dr. V.S. Vijayan(2008-2010) & Dr.R.V. Varma (2010-) for financial supports and providing technical support through their participation. We wish to thank Dr. Madhusoodhana Kurup, Honorable Vice Chancellor of Kerala University of Fisheries and Ocean Studies for his valuable advice, constant encouragement participation and whole hearted support to the event. The Dean of Fisheries College, Panagad, Dr.Namboodiri in 2008 deserves special mention for rendering required supports. The current Dean of KUFOS Prof (Dr). Jayachandran & Dr. F.G.Benno Pereira (Head, Department of Aquaculture and Fisheries of St. Albert’s College Eranakulam) deserves special mention for rendering their technical leadership and their active participation in every stage of organizing the fishcount since 2008.. We acknowledge students and teachers of Fisheries College Panangad (KUFOS), Department of Aquaculture and Fisheries of St. Albert’s College Ernakulam and The School of Environmental Science (MG University) for their active participation and providing technical assistance. We are thankful to Dr. A.P. Thomas HOD (School of Environmental Science) & the Management,( St. Albert’s College) for rendering supports. We also wish to extend our thanks to Dr. C.P. Shaji (SBB), Dr. Bindu (RARS) Vembanad Nature Club Muhamma, Rajagiri College of Social Science, (Kalamasseri), Kuttanad Foundation, Kumarakom Nature club, S.N College (Chertala ,Kumarakom St Michels H.S, Kudavachoor, S.D College, Alapuzha, P.M.T College, Mavelikkara, Govt DVHSS, Vechoor, Kottayam Nature Society, St.Joseph Public school. Pattanakkad etc for their participation in the event. We also acknowledge the distinguished persons who inaugurated the valedictory functions, Dr.K.S. Manoj M.P in 2008, Sri P Venugopal IAS (Dist. Collector, Alappuzha) in 2009, Dr. Thomas Issac, (Honarable Minister for Finance, Government of Kerala) in 2010 and Dr. Madhusoodhana Kurup (Honarable Vice Chancellor KUFOS) in 2011. The print and electronic media played an important role in making the event a success every year by giving due publicity to the Vembanad Fishcount. WE thank all of them.. Valuable insights and Suggestions from Shri K.V. Dayal, noted environmentalist, Mr. Radhakrishnan, Vembanad nature Club and K.M. Poov, Field Coordinator CERC, ATREE are greatly acknowledged. We wish to thank Mrs. Seena Karimbumkara Senior Research Associate ( ATREE) for her critical comments on the report. We express our gratitude to the Lake Protections Forums and the fishermen -the co-organisers of the Vembanad fishcount - who provided us their whole hearted support in organizing the event through out, participated in the survey and facilitated the experimental fishing and all the participants of Vembanad fish count 2008-2011.

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CERC, TEAM

Principal Investigators

Priyadarsanan Dharma Rajan, Ph.D. : piyan@atree.org (Team Leader)

Siddhartha Krishnan, Ph. D. : siddhartha.krishnan@atree.org

Kiran M.C. : kiran@atree.org

Project Coordinator

Jojo T. D. : jojo@atree.org

Research Associate

Krishna Kumar K : krishnakumar@atree.org

Programme Officers

Ashish George : ashish.mathew@atree.org

Project Assistant

Murukan Pareparambil : murukan.pp@atree.org K. M. Poovu

Support Staff Sunitha

Consultants

Sajid Pareeth Arun Sebastian Rajesh C.S.

Past Members of the team

Seema Purushothaman (Principal Investigator) Latha Bhaskar (Project Coordinator) Deepak Dayanandan (Programme Officer) Rajimol S. (Programme Officer) Simmy Solomon (Asst. Programme Officer) Monisha S. (Asst. Programme Officer) K.A. Kishore (Project Assistant) Murukesh (Project Assistant) Anitha Sarma (Consultant) Lakshmi (Consultant)

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Executive Summary

Vembanad Fish count 2008-2011 has recorded 67 species of fin fishes and 14 species of shell fishes.

Vembanad Fish Count Fin fish Shell fish

2008 50 10

2009 61 14

2010 53 14

2011 44 14

Six brackish water fish species recorded in 2009 was not observed during 2008, 2010 and 2011.

The Euryhaline conditions created by the early opening of Thannermukkom barrage which allowed salinity influx, is the reason for high fish diversity in 2009.

Total of 5 exotics viz; Pterygoplichthys multiradiatus (Sucker catfish), Catla catla (Catla), Labeo rohita ( Rohu) Oreochromis mossambicus (Tilapia) and Pangasious suchi (Suchi catfish) were observed in Vembanad Fish Count 2009. No exotic fishes were recorded in 2011.

A serious decline in the population of the dwarf puffer, Carinotetraodon travancoricus was noticed over the past three years, which comprised to 90% of the catch by experimental fishing in 2008, dwindled to 2% in 2009 and was very rare or absent in 2010 & 2011.

VFC 2008-2010 recorded 67 Species of Finfishes and 14 species of shell fishes and the earlier study Headed by Dr. Madhusoodhana Kurup, Vice Chancelor Fisheries University in 1985 and 1989 recorded 60 species.

Out of 60 Species reported in the previous studies (Kurup, 1985; Kurup 1989) 23 species are not recorded while 24 species are added in Vembanad fish counts 2008- 2011.

Clarias dussumieri, Ehirava fluviatilis, Macrognathus guentheri and Ompok bimaculatus are the four freshwater fishes missing in the lake. Of which Clarias dussumieri is completely extruded and may be locally extinct. The reasons for the missing of these species demands further research.

According to Kurup (1985 and 1985) the fish fauna of Vembanad was dominated by the marine migratory species (56%). During this survey saline tolerant/freshwater species dominates (with 69%) and the marine migrants are reduced to 31%

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Kurup et al (1989) & Kurup and Samuel(1985) recorded 49% of omnivorous fishes, followed closely by 44% carnivores and 4% herbivores and 3% detritivores. Vembanad Fish Count 2008-2011 shows a decline of carnivores (28%) and dominance of omnivores (58%) followed by 6% herbivores, 6% larvivores, and 2% detritivores. This is an indication of organic pollution of the lake.

Carry bags, bottles and other plastics dumped to the lake settles to the bottom has adversely affected the bottom feeders like gobids, and has also affected the fishes that attach their eggs to the bottom soil as the habitat changed.

Changes usage of the waterscape and surrounding landscape, Pollution from solid wastes such as plastic thrown to the lake, pesticides & fertilizer runoffs from the paddy fields, loss of mangroves, unsustainable Fishing Practices and exotic weeds and fishes are identified as the major threats to the fishery of Vembanad Lake.

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Chapter 1

Introduction

Vembanad Lake (9° 34' 60 N, 76° 25' 0 E) is

a transitional ecotone between sea and land

having a length of 96 km and a surface area of

1512 km2. The rich biodiversity and socio

economic importance, of Vembanad lake

along with adjacent kole lands led to the

declaration of the lake as a Ramsar site, a

wetland of international importance. Ten

rivers which originate from the Western

Ghats Biodiversity Hotspot drain to the lake

and eventually join the Arabian Sea. The

mangrove patches and islands in the lake like

Pathiramanal also provide habitat for resident

and seasonal migratory water fowl, otters,

fish, clams, shrimps, crabs, aquatic insects

and other aquatic organisms. The lake is also

famous for its tourism potential, live clam

resources and sub-fossil shell deposits, as a

habitat for the vulnerable spot billed pelican

Pelicanus philippensis, large populations of

water fowls, besides a high species diversity

of finfish and shellfish (WWF 2002). One

hundred and fifty species of fish belonging to

100 genera and 56 families are known to

occur in Vembanad Lake (Kurup and Samuel

1985). Extensive water and land remodeling

efforts in Vembanad Lake has drastically

changed the lake's water and landscapes,

altering natural habitats of many terrestrial

and aquatic fauna and flora. Past economic,

agricultural and industrial development has

overlooked the importance and necessity of

conservation and management of natural

resources. It was generally thought to be a

luxury, to be concerned with such matters in

the face of prevalent poverty and hunger

existed in this most densely populated area of

the state of Kerala. The more pressing

challenge for the subsequent governments

after India’s independence was to meet the

basic needs of a rapidly amplifying

population than conservation of the natural

resources. So the major anthropogenic

interventions in Vembanad region were

focused on to escalate the agricultural

production in the reclaimed areas of Kuttanad.

An artificial spillway was constructed at

Thottappally in 1955 for flood control and to

escalate agricultrural production (Gopalan et

al., 1983). But the spillway channel was not

constructed according to the required

dimensions, which resulted in the partial

evacuation of the floods. Thaneermukhom

Bund, a 1.441 km regulator cum barrage

constructed during 1976 to avert salt water

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incursion on to the paddy fields of Kuttanad,

was another major human intrusion in

Vembanad Lake. The decline in primary

productivity and fishery resources, growth of

macrophytes and degradation in water quality

are well documented consequences of this

intervention. Of 33 species of fishes reported

from Kuttanad area, the catches of several

have declined drastically. Large scale fish

mortality has also been observed on several

occasions (Azis & Nair, 1981). The tidal

flushing prevalent in the entire lower

Kuttanad region has ceased and there has

been a drop in water level in the upstream

region. In addition, drop of salinity and the

agricultural run offs from the paddy fields has

caused an unprecedented growth and spread

of noxious aquatic weeds like Salvinia

(Salvinia molesta D.Mitch.) and water

hyacinth (Eichornia crassipes (Mart.) Solms)

leading to severe eutrophication of the lake.

Apart from adversely affecting the lake

ecosystem, this has created problems for

paddy cultivation, navigation and fishing. The

oligohaline condition created by the

Thanneermukhom barrage has caused severe

setbacks to the clam production. Vembanad

wetland has been widely acclaimed as the

‘inland fish basket’ of Kerala for centuries.

But due to habitat alteration, eutrophication

and other anthropogenic stressors the fish

production has drastically reduced in the near

past. Fish production in the entire wetland has

been quantified to 7200 tons per annum.

Consequent to ecosystem alterations,an

estimate on the exploited catches of the fishes

on the southern stretches of the lake has been

found to be only 584 tons per annum,

(Padmakumar et al, 2001), a mere seven

percent of the total catch for entire Vembanad

lake. Before the construction of the barrage

southern stretches were contributing forty to

fifty percent of the total catch which

obviously indicates the extent of fishery

decline due to the construction of the barrage.

Apart from the threat posed by the barrage

there is extensive overfishing, especially

during the monsoon period even from the

spawning grounds where they congregate.

The high mortality of the broodstock and the

juveniles affects the stock for the succeeding

years, thereby reducing recruitment and, thus,

overall production. (Krishna Kumar et al.

2008) In some cases, this has contributed to

the local extirpation of certain species like

Clarias dussumieri.

Traditionally, conservation and management

of the resources of Vembanad, especially

fishery resources were vested with the local

fishing communities. These community-based

management systems evolved at the local or

grassroots level, and were actively involved in

the management of the resources they relied

on for sustenance and livelihood security.

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There were several customs and traditional

practices which were directly or indirectly

protecting the fishery resources. Such

functions, responsibilities and authority,

however, slowly changed hands and are now

vested with state government departments.

People lost the feeling of ownership and to

cope with the increasing living expenses,

changed lifestyles and scarcity of resources,

they adopted many destructive fishing

practices which have accelerated the decline

of fishery resources in the lake. In spite of the

existence of several rules and regulations for

the conservation and management of fishery

resources and regulating the use of destructive

gears, effective control mechanisms could not

be exercised as the fishermen were not

convinced of the same.

Vembanad Fish Count (VFC) Ashoka Trust for Research in Ecology and the

Environment (ATREE) initiated the

“Vembanad Fish count” in this backdrop as

an annual participatory fish assessment during

May 2008 and repeating it in every year since

then. Several institutions and agencies like the

Kerala State Biodiversity Board, Regional

Agricultural Research Station (RARS,

Kumarakam) of the Kerala Agricultural

University, Vembanad Nature Club and

various Lake Protection Forums of the fisher

folk are the co -organizers of the event.

Kerala University of Fisheries and Ocean

Sciences (KUFOS, erstwhile Fisheries

College, Panangad), St Albert’s College

(Ernakulam) and Environment Science

department of the Mahatma Gandhi

University are providing the necessary

technical support for the event. VFC is a

democratic paradigm in research and

development which is different from the

conventional top-down approaches. It is a

stakeholder driven program where the

targeted group participates in the entire

process, learning about the situation,

identifying problems, discussing alternatives,

seeking solutions, designing and

implementing activities, evaluating and

disseminating results. In these processes,

fisher folk of Vembanad share their

traditional knowledge to identify problems

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and solutions, ensuring that the poor and

uninformed will not be excluded from

decision making and development

opportunities. Such dialogue initiated during

the Vembanad fishcount has lead the

foherfolk to organize as Lake Protection

Forum(LPF). 14 units of LPFs are now

registered and are federated as Federation of

Lake Protection Forums. LPFs are taking a

leading role in organizing several

conservation programs at Vembanad. One of

the important activities of LPFs is the

Matsyathaavalam (fish sanctuaries).

Fishermen have created 6 small fish

sanctuaries (no fishing area with breeding

supports for fishes) based on their traditional

knowledge.

Researchers, NGOs, environmentalists and

media persons from allover South India and

students, fishermen, local self governments,

schools, from around the lake are

participating in this annual event and are very

eager to learn about the status of fishery

resources of the lake. This event has helped to

consolidate views on the issues and convinced

the need for immediate interventions in this

sector, especially through participation of the

stakeholders. This report acknowledges the

efforts of each and every participant of this

and appeals all concerned to initiate adequate

measures to safeguard the lake and its

biodiversity.

Coastal backwaters and inland water bodies

are economically efficient systems, now fast

declining due to lack of care, improper

management, over exploitation and lack of

awareness. One of the hopes of backwater

conservation lies in the ‘active involvement of

the dependent communities in the

management of the natural resources. This

can be made possible only by

institutionalizing community rights over

protection and harvest of the natural

resources. In the last few years, Ashoka Trust

for Research in Ecology and the Environment

(ATREE) has been trying to address some of

the conservation issues faced by Vembanad

Lake (Kerala) through a deliberative

democratic process (www.vembanad.org).

ATREE aims to increase coordination

between stakeholders and strengthen their

capacity to address the various issues related

to Vembanad backwaters and build multi

sectoral and multi stakeholder partnerships at

the local level to influence decision making.

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Objective The main objective of this participatory

assessment is ‘to bring attention to the

declining status of inland fisheries in the

Vembanad Lake and to create a common

platform to consolidate attention of all

concerned, including the policy makers to

discuss conservation issues.

Methodology Wide media publicity was given about the

‘Vembanad Fish Count 2008- 2011, inviting

participation of interested individuals.

Institutions like Fisheries college, St Albert’s

College, Ernakulam, Environmental Science

department of local Universities, Kerala State

Biodiversity Board, Regional Agricultural

Research Station, schools and colleges in

Vembanad region, Cochin University of

Science and Technology, Kerala State

Pollution Control Board and Non

Governmental Organizations etc. were

contacted, invited to participate.

Responding to the call, 120-150 volunteers

participated in every fishcount drawn from

various universities, colleges, nature clubs,

societies and NGO’s. The participants were

divided into three cruise teams, and each team

sampling from one sector of the lake viz west

bank sector (Mohamma cruise), riverine

(Kuttanad cruise) and ‘east bank (Kumarakom

cruise). Five sampling points were identified

in each sector viz. Kavanattinkara,

Kumarakom, Nazareth and Pallom in the east

bank . ‘Punnamada, Pallathuruthy, Kainakary,

Nedumudy and Pullincunnu in the riverine

stretch. Muhamma Pathiramanal Aryad and

Mannachery in the west bank.

Each cruise team was further subdivided to

assign responsibilities for 1) experimental

fishing, 2) collecting data from landing

centres, 3) collecting data from fishermen in

the lake and 4) water quality monitoring. One

week before the event, a scoping survey was

conducted to identify the key landing centers

around the lake. Camps were arranged near

the landing centres and team left early in the

previous evening, to collect data from early

morning hours on the fishcount day.

The rest of the cruise teams were flagged off

from Mohamma at 6 AM and survey

concluded at 3 PM. For fish sampling and

inventory of species the methodology of

Meeenachil Fish count, 2004 (Padmakumar et

al 2006) and River fish Monitoring Program (

Bijukumar et al 2010 ) was used with due

modifications to suit to the estuarine system.

At most possible care was taken to ensure that

the sampling effort was uniform through out.

Experimental fishing (undertaken by local

fishers) was carried out from 4 AM to 12 PM

on 30th May 2008, 26th May 2009, 28th May

2010 and 26th May 2011 at the various

sampling sites mentioned above using variety

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of gears including gill net, cast net, drag net

and scoop net.

Resource use inventory was carried out

wherein the number of sand mining units,

shell mining units, house boats , number of

fishing units, encroachments, waste dumping

activities and extent of weed cover was

observed and assessed using detailed

observation schedule.

Fishing ground inventory was carried out

with the due participation of local fishers who

allowed us to check the species, which

contributed to their catch on that day. An

Identification key prepared for fish count was

referred to identify the fish. Enquiries were

also made on the fishing methods and socio-

economic information of the fishers.

Landing centre inventory - The major

landing centers around the sampling sites

were also visited on 30th May 2008, 26th

May 2009, 28th May 2010 and 26th May

2011 and the species diversity of the catches

were recorded. The type of gear used and the

percentage of commercially important fishes

to the catches were recorded in consultation

with the fishers.

Water Qualaity

The data generated from the Jaladarpanam

water quality monitoring program of Lake

Protection Forum (LPF) and the data

generated during fishcounts also used for the

analysis of water quality presented in the

chapter 2.

Jala darpanam (Vembanad Water Watch):

The Members of Lake protection forum are

now trained in monitoring the water quality of

lake, are doing a regular analysis of lake

water quality and display it in village

information boards set up for this. The data is

also made available to the public through

India BiodiversityPortal

(http://indiabiodiversity.org/layer_info.php?la

yer_name=lyr_50_vembanad_basinstations).

The community is using this information as a

tool for better bargaining with authorities for

scheduling the operation of the

Thanneermukkom bund, which is critical for

the paddy cultivation as well as fishery wealth

of the lake.

Water quality parameters tested includes

parameters like pH, transparency,

temperature, D.O, Alkalinity and salinity. pH

was determined using pH paper,

Transparency using Secchi Disc and

Temperature using Mercury Thermometer ,

Dissolved Oxygen, Alkalinity as CaCo3 ,

salinity were determined using standard

procedures at the sampling sites. And the

parameters like Chloride, Alkalinity,

Hardness, Calcium, Magnesium, Phosphate,

Sulphate and Iron was determined by using

the water quality analysis kit made by CPR

Environment Education Centre.

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Chapter 2

2.1 Physiochemical Environment TDS: The expression, “total dissolved solids”

(TDS), is the total amount of all inorganic and

organic substances – including minerals, salts,

metals, cations or anions – that are contained

within a volume of water. TDS concentrations

are used to evaluate the quality of freshwater

systems. TDS concentrations are equal to the

sum of positively charged ions (cations) and

negatively charged ions (anions) in the water.

Sources for TDS include agricultural run-off,

urban run-off, industrial wastewater, sewage,

and natural sources such as leaves, silt,

plankton, and rocks. High concentrations of

particulate matter affect light penetration and

productivity, recreational values, and habitat

quality, and cause lakes to fill in faster.

Particles also provide substratum for other

pollutants, notably metals and bacteria. While

TDS is not considered as a primary pollutant,

Figure 1 . TDS levels in Vembanad lake

(October 2009 to September 2010)

high TDS levels typically indicate hard water.

TDS levels more than 1000mg/l is considered

to be not favorable for the aquatic organisms.

The TDS in Vembanad lake tend to increase

between the month of December to May in all

the sampling stations. TDS value is low

during the months of June to November. This

clearly shows the effect of Thanneermukkom

salt water barrier as the TDS shoots up during

the season when the bund is closed. The

average value of TDS in the lake is around

2500 mg/l and Thanneermukkom shows the

maximum TDS in March, April and May.

Lowest TDS is observed in Kainakary. The

graph ( fig. 1) shows the monthly fluctuations

in TDS values in Vembanad lake.

Nitrates and Nitrites: Nitrate (NO3) and

nitrite (NO2) are produced as a result of

biological breakdown of organic wastes

containing ammonia such as e, animal feces

or fertilizers containing these chemicals.

Although not particularly toxic to aquatic

organisms, excess nitrates and nitrites in the

water is often used as an indicator of poor

water quality. The permissible limit of nitrate

is 50 mg/l. Levels exceeding 0.55 mg/l (ppm)

nitrite-nitrogen can cause 'brown-blood'

disease in finfish.

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Figure.3 Nitrate level in Vembanad lake (October 2009- September 2010

Figure 2 . Nitrate levels in Vembanad lake

(October 2009 to September 2010) Anaerobic conditions may result in the

formation and persistence of nitrite. The

presence of large quantities of nitrites in

Vembanad lake is indicative of water

pollution due to possible agricultural run off

from the adjoining paddy field in

Kuttanad.The primary health concern

regarding nitrate and nitrite is the formation

of methaemoglobinaemia, which is also

known as “blue-baby syndrome.” Nitrate is

reduced to nitrite in the stomach of infants,

and nitrite is able to oxidize haemoglobin

(Hb) to methaemoglobin (metHb), which is

unable to transport oxygen. The reduced

oxygen transport becomes clinically manifest

when metHb concentrations reach 10% or

more of normal Hb concentrations; the

condition, called methaemoglobinaemia,

causes cyanosis (appearance of a blue or

purple coloration to the skin due to oxygen

deficiency) and, at higher concentrations,

asphyxia, a condition of severely deficient

supply of oxygen to the body.

The normal metHb level in infants under 3

months of age is less than 3%. The Hb of

young infants is more susceptible to metHb

formation than that of older children and

adults.

The concentration of nitrate and nitrite tend to

increase during the months of January and

February when the water influx from the

rivers is low, and is absent in the lake during

the monsoon months of July, August and

September. The possible reason for increase

of nitrogenous compounds is mainly due to

the use of nitrogen based fertilizers in the

paddy field. As the flow of water is regulated

during the months of December to March

these pollutants are integrated with the lake

water. (fig 2 & 3)The presence of these

pollutants can result in algal blooms and

result in further disasters like mass mortality

in fish, foul smell in water etc.

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Phosphate: High phosphate concentration in

surface waters also indicate fertilizer runoff,

domestic waste discharge, or the presence of

industrial effluents or detergents. If high

phosphate levels persist, algae and other

aquatic life will flourish, eventually

decreasing the level of dissolved oxygen due

to the accelerated decay of organic matter.

Algal blooms are encouraged by levels of

phosphate greater than 25 micrograms/L. The

phosphate level above 0.1 mg/l is regarded as

unhealthy. The concentrations of phosphate

tend to increase during the months of January,

February, March and April and show a

declining trend from May. ( fig 4)Phosphate

is found to be absent in the lake during the

months of August, September, October,

November and December. The possible

reason for increase of phosphate is mainly due

to the use of chemical fertilizers. As the flow

of water is regulated during the months of

December to March phosphate gets blended

with the lake water. The presence of excess

phosphate can result in algal blooms and

result in

further catastrophe like mass mortality in fish,

foul smell in water etc.

Sulphate: The increased concentration of

sulphate is due to the flushing off water from

the agricultural lands. This can result in the

eutrophication a state in which the nutrient

content of the system reaches the peak and

which results in algal bloom and adversely

affect the ecosystem and organisms. The

concentration of sulphate tends to increase

during the months of March and Figure 5 . Sulphate levels in Vembanad lake

(October 2009 to September 2010)

April and shows a declining trend from

May.(fig 5)

Dissolved oxygen (DO) is the relative

amount of oxygen dissolved in water. Oxygen

enters the water by diffusion from the

atmosphere or through plant photosynthesis.

Actual solubility is directly proportional to

the partial pressure in the gas phase, to salt

Figure 4 . Phosphate levels in Vembanad lake (October 2009 to September 2010)

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concentration and temperature. The dissolved

oxygen level in water is constantly changing

and represents a balance between respiration

and decomposition that deplete oxygen and

photosynthetic activity that increases it. So

DO is vital to aquatic life. Presence of organic

waste in water may overload a natural system

causing serious depletion of the oxygen

supply that in turn leads to fish kills.

Likewise, eutrophic waters, rich in nutrients,

achieve the same result through causing

massive proliferation of algae (algal blooms)

whose eventual decomposition uses up the

available dissolved oxygen.

A DO content of greater than 5 mg/l in water

is required for sustaining aquatic Fauna. Like

terrestrial animals, fish and other aquatic

organisms need oxygen to live. As water

moves past their gills (or other breathing

apparatus), microscopic bubbles of oxygen

gas in the water are transferred from the water

to their blood. Like any other gas diffusion

process, the transfer is efficient only above

certain concentrations.

In other words, oxygen can be present in the

water, but at too low a concentration to

sustain aquatic life. Oxygen also is needed for

many chemical reactions that are important to

lake functioning. Oxygen is produced during

photosynthesis and consumed during

respiration and decomposition. As it requires

sunlight, photosynthesis occurs only during

daylight hours. Respiration and

decomposition, on the other hand, occur 24

hours a day. This difference alone can

account for large daily fluctuations in DO

Figure 6 . DO levels in Vembanad lake

(October 2009 to September 2010

concentrations. During the night, when

photosynthesis cannot counterbalance the loss

of oxygen through respiration and

decomposition, DO concentrations steadily

declines.

They are lowest just before dawn, when

photosynthesis resumes. To the degree that

pollution contributes oxygen-demanding

organic matter (like sewage or lawn

clippings) or nutrients that stimulate growth

of organic matter, causes a decrease in

average DO concentrations. If the organic

matter is formed in the lake, for example by

19

19

algae growth, at least some oxygen is

produced during the growth to offset the

eventual loss of oxygen during

decomposition. However, in lakes where a

large portion of the organic matter is brought

in from outside the lake, the balance between

oxygen production and oxygen consumption

becomes skewed and low DO may become

even more of a problem. The DO found in

Vembanad lake is stable and is sufficient for

sustaining aquatic life.( fig. 6) A DO of

8mg/l was observed in two sites- Muhamma

in February and Thannermukkom in March.

The lowest DO was recorded at Kumarakom

(3mg/l) in November.

Biological Oxygen Demand (BOD): BOD

measures the amount of oxygen utilized by

organisms in the biochemical oxidation of

organic matter in a wastewater sample in a

specified time (usually 5 days), and at a

specified temperature. BOD measurements

are used as a measure of the organic strength

of the water. Although it is not identical to

COD, the speed at which one can obtain COD

test results, often dictates that this test is used

for prescription purposes. Typical natural

water has a BOD from 0.8 to 5 mg/l.

Anything above 6 mg/l needs to be treated as

unsafe as it will rob the water of needed

oxygen. Similar to DO, BOD in Vembanad

lake also is stable. A BOD of 0mg/l was

observed in Kumarakam and Kainakary in

October. The Highest BOD (4mg/l) was

recorded at Muhamma in October and

Thannermukkom in December.

Figure 7. BOD levels in Vembanad lake

(October 2009 to September 2010

2.2 Microbial Pollutants

The quantity of faecal coliform bacteria

Escherichia coli (E. coli) in the water is a

recommended indicator of fecal

contamination for waters. E. coli is present in

high numbers in the gastrointestinal tracts of

warm-blooded animals and they can survive

in the waste material or water contaminated

with feces for a limited time and therefore is a

good indicator of fecal contamination of

water. Sources of E. coli that can impact lake

water are numerous and can include

combined sewer overflows; sanitary sewer

overflows, leaking septic systems, water

drained down from Pampa river during

Sabarimala pilgrimage seasons, waste

20

20

discharge by houseboats, storm water runoff,

agricultural runoff, wildlife, and domestic

pets.Another important source for the

increased level of feacal coliforms are illegal

house boats without proper bio tanks and the

people who discharges human waste directly

to the Lake. Most probable number is the

method used to estimate the amount of feacal

coliforms. The permissible level of coliforms

in recreational waters is 400 and is nil for

drinking water. But the level of coliforms in

the Vembanad lake is far beyond this i.e.

above 1100. Although not necessarily agents

of disease, fecal coliform bacteria may

indicate the potential presence of disease-

carrying organisms such as V. cholerae,

which live in the same environment as the

feacal coliform bacteria.

The studies also indicate that the lake is

highly polluted during the month of October

with bacteria contamination at the sites like

Pallathurithy, Punnamada, Muhamma,

Thannermukkom and Kumarakom. Vibrio

cholerae the cholera causing bacterium is

found in every site. This is an alarming

situation, as there are chances of cholera

infection among people who use this water

for drinking, washing kitchen utensils and

accidental ingestion while bathing and

swimming. The lack of proper sewage

systems in the lakeside towns and the toilets

directly opening to the lake s the reason for

high bacterial contamination of the lake. The

presence of V. cholereae is found at

Pallathuruthy region which is fed with water

from river Pampa. The extent of V. cholereae

in Vembanad lake is very high compared to

the permissible levels.. An outbreak was

reported in 2009 and the chances of cholera

outbreak in the fringes of Vembanad lake still

exists.

21

21

Chapter 3

VEMBANAD FISH COUNT 2008-2011 Vembanad fish 2008-2011has so far has recorded 67 species of fishes belonging to 46 genera and

34 families. The list also includes 2 introduced fishes viz; Catla catla (Katla) and Labeo rohita

(Rohu) and 3 exotic fishes viz; Pangasianodon hypophthalmus (the Sutchi catfish), Oreochromis

mossambicus,( Tilapia) and Pterygoplichthys multiradiatus (suckermouth catfish). Species list is

provided on Table 1 and an annotated check list of fishes of Vembanad is given in Annexure 1.

22

Table 1. Fish fauna of Vembanad lake and its presence and absence in VFC 2008-2011

Si No Species 2008 2009 2010 2011

1. Alepes djedaba √

2. Ambassis ambassis √ √ √ √

3. Amblypharyngodon melettinus √ √ √ √

4. Amblypharyngodon mola √ √ √

5. Anabas testudineus √ √ √ √

6. Aplocheilus lineatus √ √ √ √

7. Aplocheilus panchax √

8. Arius maculates √ √ √

9. Arius subrostratus √ √ √ √

10. Balistes capriscus √

11. Brachirus orientalis √ √ √ √

12. Butis butis √ √

13. Carangoides malabaricus √ √ √

14. Carinotetraodon travancoricus √ √ √ √

15. Catla catla √ √

16. Channa marulius √ √ √ √

17. Channa gachua √

18. Channa striata √ √ √ √

19. Chanos chanos √ √ √

20. Chelonodon patoca √

21. Cynoglossus macrostomus √ √ √ √

22. Dayella malabarica √ √ √ √

23. Etroplus maculates √ √ √ √

24. Etroplus suratensis √ √ √ √

25. Eubleekeria splendens √ √ √ √

26. Gerres filamentosus √ √ √ √

27. Gerres setifer √ √ √

28. Glossogobius giuris √ √ √ √

23

29. Heteropneustes fossilis √ √ √ √

30. Horabagrus brachysoma √ √ √ √

31. Hyporamphus xanthopterus √ √ √ √

32. Hyporhamphus limbatus √

33. Johnius dussumieri √ √

34. Labeo dussumieri √ √ √ √

35. Labeo rohita √

36. Labuca dadiburjori √

37. Lates calcarifer √

38. Mastacembelus armatus √ √ √ √

39. Mugil cephalus √ √ √

40. Mystus armatus √ √ √ √

41. Mystus gulio √ √ √ √

42. Mystus vittatus √ √ √

43. Nandus nandus √ √ √ √

44. Ompok malabaricus √ √ √ √

45. Oreochromis mossambicus √ √

46. Pangasianodon hypophthalmus √

47. Parambassis dayi √ √ √ √

48. Pseudoambassis ranga √ √ √ √

49. Parambassis thomassi √ √ √ √

50. Photopectoralis bindus √ √ √

51. Pristolepis rubripinnis √ √ √

52. Pseudosphromenus cupanus √ √ √ √

53. Pseudosphromenus dayi √ √ √

54. Pterygoplichthys multiradiatus √

55. Puntius amphibius √ √ √ √

56. Puntius filamentosus √ √ √ √

57. Puntius mahechola √ √ √

58. Puntius sarana sarana √ √ √ √

59. Puntius sarana subnasutus √ √

24

60. Puntius ticto √ √ √

61. Puntius vittatus √ √ √ √

62. Rasbora daniconius √ √ √ √

63. Scatophagus argus √ √ √

64. Siganus javus √

65. Stolephorus indicus √ √ √ √

66. Wallago attu √ √ √ √

67. Xenentodon cancilla √ √ √ √

Shell Fishes

1. Metapenaeus dobsonii √ √ √ √

2. M. monoceros √ √ √

3. Penaeus monodon √ √ √ √

4. Fenneropenaeus indicus √ √ √ √

5. Macrobrachium rosenbergii √ √ √ √

6. M. idella √ √ √ √

7. Leptocarpus potamiscus √ √ √ √

8. Caridina naderjoni √ √ √ √

9. C. pseudo-gracilirostris √ √ √

10. Scylla serrata √ √ √ √

11. S.tranquebarica √ √ √

12. Villorita cyprinoides √ √ √ √

13. Lamelliden marginalis √ √ √ √

14. Pila globosa √ √ √ √

25

3.1 Fish Fauna of Vembanad Lake.

Fishes of Vembanad Lake play a crucial role

in sustaining the livelihood of the fishermen

residing along the lake and maintaining its

ecosystem health of the Vembanad Lake .

Lack of data about the status of fishes of

Vembanad Lake in public domain raised lot

of wrong assumptions about fish fauna of the

lake. Swaminathan Commission Report

mentions that “The multiple reports have

recorded that 23 species of fishes have

become extinct as water body got shrunk, the

fish population and diversity got reduced”.

Statement like this might mislead as the

document doesn’t show the list of fishes that

got extinct or no supportive evidences are

available to establish this. Studies in recent

past have demonstrated that any premature

claims of local extinction of fish species

should be cautiously verified before

conservation measures are prescribed (Knight

2010; Knight & Remadevi 2010).

The fishery decline in the lake is due to many

stressors like habitat alterations,

overexploitation, pollution, introduction of

exotic fishes, (Padmakumar et al 2001,

Krishnakumar et al 2008, Krishnakumar et al

2011) etc..

More than 30% of the lake’s ichthyofauna is

represented by catfishes belonging to the

family Hetropneustidae, Siluridae and

Bagridae ( 11 Spceies) barbs belonging to the

family Cyprinidae with 10 species. Cyprinids

unlike most other fish species, increase in

abundance in eutrophic conditions. This can

be attributed to the abundance of their food

resources- the zooplanktons which grazes on

the algae which blooms in the eutrophic

conditions. Catfishes also can survive in

polluted or eutrophic conditions. 3 species of

snake heads which can survive in adverse

conditions also accounts to the fauna of the

lake. The lake also have 4 species of glass

fishes which occurs in standing water, and

breeds prolifically during the rainy season and

feeds on crustaceans, annelid worms, and

other invertebrates. The lake has 3 species of

cichlids. Once renowned for its mullets and

sea bass lost its pride after the construction of

the Thanneermukkom. The population of thse

fishes has gone down drastically and has

become extremely rare in the lake. The stable

or mere increase in number of species can not

be taken as an indicator of a healthy situation

of fishery in Vembanad lake. The stock of

many fish species have dwindled in the last

decade. Unsustainable fishing methods

practiced by the fishers to tackle the scarcity

of resources exacerbated the situation

resulting in abrupt exhaustion of

economically viable fish species.

26

3.2 Changes in fish Fauna of Vembanad

Kuttanad Water Balance study (1985-1989)

recorded 60 species of fishes from the

southern sector of the lake i.e. the region from

Thanneermukkom to Kuttanad. The study

also recorded 150 species of fishes from the

entire Vembanad Lake. The fish faunal

diversity and composition of the lake has

changed during 2008-2011 as the number of

fishes in the lake has heaved to 67species.

Among this 5species added to this list are

those got introduced to the lake intentionally

(ranching) or unintentionally (accidental

escape from culture ponds/aquaria). Tilapia

(Oreochromis mossambicus) was the only

exotic fish that occurred in the lake during

1980’s but the scenario changed after two

decades 4 introduced fishes was recorded

from the lake during 2008-2011. Another

alarming fact is that 28 species reported from

the lake during 1985-1989 is not recovered

during this survey. An analysis of the missing

species revealed that 86% (fig 8) of the

missing fishes are migratory fishes from the

sea to the freshwater zones (for spawning and

feeding). Thannermukkom barrier prevents

the entry of these marine migrants to the lake.

The resident fishes those are missing in the

survey includes Clarias dussumieri, Ehirava

fluviatilis, Macrognathus guentheri and

Ompok

Figure 8. Composition of fishes missing in

Vembanad Lake after 1989

bimaculatus of which Clarias dussumieri is

extirpated completely and locally extinct in

the lake as there are no records of the species

from the lake since 2005. The exact reason

behind the local extinction of Clarias

dussumieri an omnivorous fish is not known.

It is widely assumed by the fishery experts

that the species didn’t recover itself from the

epizootic ulcerative syndrome that affected

the fish fauna of the lake in 1991. Missing of

Ehirava fluviatilis, Macrognathus guentheri

and Ompok bimaculatus in the lake requires

further studies. There is considerable chances

Figure 9. Composition of fishes

VFC 2008-2011

27

of taxonomic error in identifying the species

as the some individuals identified as

Mastacembelus arnatus and Ompok

malabaricus may actually have been ,

Macrognathus guentheri and Ompok

bimaculatus respectively as both species has

been recorded in all previous surveys. 24

fishes were added to the fauna of Vembanad

through fish count since the 1989 effort.

The list (VFC 2008-2011) is dominated by

the freshwater fishes. 69% (fig 9). The

southern sector of the lake is enriched with

freshwater from 4 rivers that

drain into the lake which makes it an

idealhabitat for freshwater fish species

Figure 10. Composition of fishes

Kurup 1985 and 1989

.

In 1985 and 1989 the fish fauna of the lake

was dominated by the migratory species

(56%). ( fig 10) but in the last two decades

the trend has got reversed and now the lake is

dominated by the resident fish species (69%).

(Fig 9)

Among the 24 fishes added, only 6 species

constitute the marine migrants and 18

Figure 11. Composition of fishes added to

Vembanad Lake after 1989

species are freshwater fishes with minor value

to fisheries ( Fig 11) while fishes absent in

the lake are fishes with high fishery value and

in 1980’s these fishes played a significant role

in sustaining the livelihood of the fisherfolk

of the Vembanad.

The fishery wealth of the lake helped to

affirm its status as an inland ‘fish basket’ of

Kerala by contributing significantly to the

bulk of the inland fishery catch of the state. .

This survey during 2008-2011 shows that the

the composition of species of lesser or minor

fishery importance has become more

abundant. Composition shows that the

southern side of the barrage is converted to a

fresh water lake with occasional influx of

salinity which is not certain. The climatic

changes also cascades this action as heavy

summer rains in the recent years and the

prolonged monsoon similar to the one in

28

2010-2011 prevent saline intrusion into the

lake even when the barrier is open

Figure 11.Feeding Guild of fishes

VFC 2008-2011

A swing in the feeding guild also is evident in

the composition of fishes in Vembanad

between 1985 and 2011. as Kurup et al(1989)

& Kurup and Samuel (1985) have recorded

49% of omnivorous fishes, followed by

carnivores 44%, herbivores (4%) and

detritivores (3%). ( Fig 13) The VFC- 2008-

2011 has recorded 58% omnivores 28%

carnivores and 6% herbivores, 6% larvivores,

and 2% detritivores. ( Fig 12)

An analysis of the feeding guild of the the 29

species missing after 1989( fig 14) studies

shows that 62% of those were carnivores

while 35% were omnivores and 3%

detritivores. Whereas among the 23 fishes

(excluding the exotics) newly reported during

subsequent VFC’s, omnivores dominate with

44% followed by carnivores (35%) and

larvivores (17%) and herbivores (4%).( fig

15.) The presence of carnivores indicates the

health of the ecosystem as the ecosystem

integrity is often dependent on the functional

presence of carnivores. Removal of the

predators results in dissolving the ecological

boundaries that check competition. By

consuming the smaller fishes and other

organisms in the lake through selective

feeding. Decline in population of Carnivores

Figure 13. Feeding guild of fishes Kurup ( 1985

and 1989)

has thus reduce the numerical abundance of a

competitively dominant prey species (or by

change its behavior) and enforce ecological

boundaries that allow weaker competitors to

persist. If a predator selects from a wide-

range of prey species, the presence of the

predator may cause all prey species to reduce

their respective niches and thus reduce

competition among those species, which can

help in the survival of the less dominant

species. The present state is that the lake is

proliferated with smaller barbs and the

29

number of carnivores reduced so that erection

of ecological boundary is not easily possible.

The contamination of the lake in the past few

years has turned the lake into an organic

plunk which helped in the proliferation of the

omnivorous fishes as they have a wide

spectrum of dietary material.

Figure 13. Feeding guild of fishes added to the

lake after Kurup ( 1985 and 1989)

The scenario might intensify in due course as the organic load in the lake is increases the omnivores will proliferate further causing a decline in the diversity and abundance of other fishes. A gradual shift in the abundant fish species in the lake is already evident. Kurup et. al. (1989) has recorded that the southern sector fishery is dominated by the native catfishes, pearl spot and carplets. Subsequent VFCs found that the fishery has shifted to smaller barbs like filamentous barb which proliferated the lake in the high organic condition. The catfish fishery which was dominant in the lake has considerably reduced to an uneconomical low. The decline in affected the as they along with frogs of Vembanad larvivorous fishes played a

significant role in controlling the mosquitoes in the region. The increase in mosquito bone diseases in vembanad region can be attributed to the decline of larvivorus fishes and frogs in

the lake.

Figure 13. Feeding guild of fishes added to the

lake after Kurup ( 1985 and 1989)

30

Chapter 4

Threats to Fishes of Vembanad

4.1 Changes in Waterscape & Habitat

Alteration

The major threat to fishes of Vembanad is

habitat alteration due to changes in

waterscape. Thousands of hectares of the

waterbody had been converted to land over

past 150 years. According to one study

(Gopalan et al., 1983), 23000 ha of the lake

had reclaimed between 1834 and 1984,

mainly for agriculture and aquaculture. The

depth of the lagoon has reduced by 40-50

percent in all zones and as a result the

drainage capacity of the lake has been

reduced to 0.6 km³ from 2.4 km³, a decline of

75 percent (James et al., 1997). Illegal

Conversion and encroachment of the lake is

visible around the lake even today.

Conversion for expanding agriculture has

slowed down but reclamation still continue

for other purposes.

The construction of the Thaneermukkom

barrage and Thottappally spillway has

changed the physico-chemical conditions of

the lake. Another importatn change is the

destruction of mangroves and its associates

that was abundant on the shores of the lake.

4.1 a Thannermukkom Barrage

The Thanneermukkom barrier was

constructed in 1976 (partially completed) to

prevent saline water intrusion into paddy

fields during the dry season, and thus bolster

paddy cultivation. The closing of the barrier

stops the tidal effects, stops the flow of water

to the south of the barrier, and thus hinders

natural flushing out of contaminants. The

accumulation of agro-chemical effluents from

the southern farmlands and sewage from

adjacent areas leads to increased levels of

water pollution. Within few decades of its

construction, the area south of the bund

became a hotspot of vector and waterborne

diseases. Preventing the entry of saline water

to the paddy fields led to an increase in pests

and weeds, which had to be subsequently

eradicated through the heavy use of pesticides

and weedicides. This has subsequently

affected the general health and livelihood of

the people, with the worst affected being the

fishermen communities due to the decline of

many commercially important fishes. The

barrier is regulated by a committee headed by

the District Collector and supposed to remains

closed from mid December to mid March.The

operation of the barrage is connected with the

31

crop calendar of and many farmers fail to

follow the calendar due to other reasons such

as labour shortage, non availability of seeds in

time etc. This results in deviations in the

operational schedules causing keeping the

bund closed for longer periods. The closure of

the barrage during the month of December

blocks the high tide that occurs in the

southern coast of Lakshadeep sea from

entering to the southern sector of lake which

prevents the entry of migratory fishes to the

lake.

Figure 16. Composition of fishes and salinity

The significance of saline intrusion to lake

for fishery evidenced by the data generated

from the last four VFCs . As VFC 2008

yielded 51 species of finfish of which 13

species was represented by the marine

migrants. VFC 2009 could identify 61 species

of finfish. The increase in the number of

species in 2009 was the result of an early

opening of Thannermukkom barrage which

allowed salinity influx ( fig 16) and helped in

the occurrence of euryhaline condition. 19

marine migrants was reported in this year

even though the salinity gradient of the lake

ranged from 1-3 ppt salinity from all the sitses

except PallathuruthyIf atleast a saline gradient

of 1-3 is maintained in the lake it will help in

maintaining the icthyofauna of the lake. Six

brackish water fish species recorded in 2009

was Figure 17 Composition of Fishes

VFC 2008-2011

The count in 2010 recorded 53 species of fin fish of which only 14 species represent the marine migrants. (fig 17)

The saline gradient was 0-2ppt and only the

region adjoining the barrage recorded the

salinity of 2ppt, while all other zones showed

zero salinity. The count in 2011 recorded the

least number of migratory fish species (7 sp.)

and the salinity was the lowest.The local

climatic changes also cascades this action as

heavy summer rains prevent saline intrusion

into the lake even when the barrage is open

and the prolonged monsoon like what we had

32

in 2010-2011 also prevents the saline influx

in the southern sector. The construction of the

barrage is not complete as per the design. To

facilitate an early commissioning to satisfy

the pressure lobbies of the farmers the middle

of the lake was reclined in haste forming an

artificial island. This permanent structure

considerably hampered the flushing efficiency

of the barrage. Thus reduced flushing out of

nutrients and pollutants from the lake causes

eutrophication. Moreover the region near the

barrage has no saline influx during the

months of December to May. Which will

bluff the fresh water fishes that breed in

April-May Lay eggs in the freshwater zone

near the barrage get a salinity shock by the

sudden intrusion of salinity, which is fatal for

the larvae/eggs.. The Pathiramanl

Island, the only patch were mangrove and

associates flourished once is not far from the

barrage and Many freshwater fishes of

Vembanad are open egg scatters and doesn’t

show parental care which intensify the issue

as the large adults will migrate to the upper

reaches of the lake and the eggs and larvae are

left over in these zones to face the detrimental

effect saline shock.

4.1 b. Agiculture & Reclamation

The main economic activity in this wetland is

paddy cultivation. To increase the

productivity, farmers depend on heavy use of

chemical fertilizers and pesticides, which in

turn pollutes the water and environment.

Reclamation for agricultural purposes started

as a result of severe food crisis existed in

India. This resulted in largescale reclamation

of Vembanad lake and its backwaters nd

resulted in the shrinkage lake area.to 180 km2

(43% of original) in 1983 (Gopalan et al.,

1983). Of the 130 km2 surveyed in 1998,

anotehr 14% (18 km2) has been observed to

be reclaimed by both natural and artificial

processes (Asharaf, 1998). The reclamation of

wetlands for various purposes still prevails in

the lake and the need for reclamation shifted

from agricultural uses to other economic

activities like tourism.

4.1 c Destruction of Mangrove and its

associates

Mangrove and its associates are important to

fishery as it provides rich source of food,

breeding and nursery areas and refuge from

predation for shrimp, crustaceans, mollusks,

and fishes and provide a.The shores of

Vembanad Lake had large extend of

mangroves and associates. Large scale

removal of these medium height shrubs

around the lake has resulted in lack of

nursery grounds for the fishes which is

detrimental to the fishery wealth. Restoration

of mangroves around the lake should be

33

considered as an important activity for lake

restoration.

4.2 Over Exploitation and Unsustainable

Fishing Practices

Overfishing and using unethical fishing

methods in Vembanad is another reason

thecurrent distress in fishery. It is evident

that the Unsustainable fishing practices

deployed by the fishers to tackle the scarcity

of resources exacerbated the situation

resulting in abrupt exhaustion of

economically viable fishes. Commons like

Vembanad have to face extensive

challenges—particularly in terms of resource

depletion and conflict between stakeholders.

The “Tragedy of the Commons” (Hardin

1968), is true with Vembanad lake also,

where individual users see no advantage to

conserve or manage the resource sustainably.

The op–down management has not resulted in

sustainable and socially equitable fisheries.

Even though participative co-management

arrangements, in which the responsibility of

resource management is shared among the

state, local resource users, and other

stakeholders, incorporating local knowledge,

characteristics of the resources and the social

groups involved, was found to be successful

in forest ecosystems in Kerala. But there are

no such efforts to implemet such governance

system for managing fisheries.

The traditional peruvala/ kettu Vala /Adakkam

kolli Vala a seine net having mesh size of

4mm and a length of 50-75m are the most

commonly used gears to catch small small

fishes. The net don’t allow the escape of small

fishes ,fry, fingerlings etc. The major fishes

exploited by this gear are Etroplus suratensis

Wallago attu, Horabagrus brachysoma,

Labeo dussumeiri, Mystus cavasius,

Amblypharyngodon mellitinus, Puntius

sarana , Puntiius filamentosis , Ompok

malabaricus, Ompok bimaculatus, Etroplus

maculatusmaculatus, Pristolepis marginata,

Nandus nandus. Even though this gear is

banned by Government of India, proper

enforcement has not yet been achieved in

regulating this gear. The use of this gear is a

threat to the biodiversity as it has been

observed during post monsoon season(August

– September) when a large number of juvenile

bye catch were found among the catch.

Many indigenous communities across the

globe have been using many poisonous plants

as ‘fish poisons’ for fishing. As time passed,

chemical poisons replaced the plant poisons.

Fish poisons are used in shallow, stagnant and

slow flowing waters. Mass poisoning kills the

fishes and larvae, around the major river

systems as well as lakes and estuaries. .Root

of bamboo as well as fruits of sapindas and

entire Acasia torta plant are used as

fishpoisons. Several kilograms of these plant

34

parts are used in order to catch fishes, the

usage at different river systems is based upon

the local availability of the plant. Poisons are

mainly used to catch fin fishes like Channa

punctatus , Channa marulius Channa

micropeltes ,Channa striatus Horabagrus

brachysoma Hetropneustes fossilis , Labeo

dussumieri , ,Wallago attu , Puntius sarana

,Puntius filamentosus ,Etroplus suratensis

etc. Copper sulphate is a chemical used in

shallow and lower reaches of rivers. It is not

commonly used by the traditional fishermen

in Vemband but the migratory fisher groups

coming from nearby states Karnataka and

Tamil Nadu use it .They use small round

boats made of bamboo locally known as

kottavallam ( coracle). They will set gill net

cross the river and from a distance they will

put copper sulphate which is wrapped in cloth

.The presence of copper sulphate will make

the fish run away from the site and while

escaping from the region they get entangled

on the gill net that has already been set.

CuSo4 a strong algicide will affect the water

quality of that area and mass destruction of

small fishes and other aquatic organisms .This

practice is intended to catch Horabagrus

brachysoma Hetropneustes fossilis , Labeo

dussumieri ,Wallago attu , Puntius sarana

,Puntius filamentosus ,Etroplus suratensis ,

Anabas testudineus , etc. The after effect of

using copper sulphate is so adverse as all the

fishes inhabiting in that region will eventually

die due to the intoxication. In some areas

certain pesticides are also use ‘fish poisons’

for fishing.

4.3 Pollution

The problems faced by organic pollution of

the lake is discussed earlier. The inorganic

materials like plastics that are dumped to the

lake gets settled to the bottom of the lake has

adversely affected the bottom feeders like

gobids, and has also affected the fishes that

attach their eggs to the bottom soil as the

habitat changed. Fishes get attracted tothe

plastic bags that are thrown to the lake with

food remnants get entangled and dies. Many

such bags with dead fishes entangles in it

were found during the VFCs and according to

fisherman fish mortality due to plastic bags

are increasing day by day High concentration

of plastics in the lake bed affects the fish by

destroying its natural environment. Pollution

from pesticides, weedicides and fungicides

too affect the fishes as the rigorous use of

these agrochemicals in to which the fishes are

sensitive. Earlier many fishes were using

paddy fields as breeding and nursery grounds

Than cradles of fshes, the over use of

pesticies has eventually converted the paddy

fields to a graveyard of fishes Use of these

non target chemicals destroys the aquatic

invertebrates which prove vital for the

35

survival of many fishes. Use of pesticides and

weedicides also resulted in the decline in

larvivorous fishes which are known to harbor

small canals and channels inside and

adjoining the fields.

4.4 Exotic Fishes

A total of 5 exotics are reported from the

lake,which includes 2 transplanted fishes viz;

Catla catla and Labeo rohita and 3 aquarium

scapes viz; Pangassious suchi, Oreochromis

mossambicus, and Pterygoplichthys

multiradiatus. Apart from these two exotics

viz; Clarias garipinus and Trichogaster

trichopterus were reported from the lake in an

independent study( Krishnakumar et al2009,

Krishnakumar et al2011). These invasive

species, i.e. non-native species that spread

beyond the introduction site and become

abundant (Rejma´ nek et al., 2002) are

increasingly recognized as one of the main

threats to biodiversity and a global challenge.

An invasive alien species is an alien species

which becomes established in natural or semi-

natural ecosystems or habitats, is an agent of

change, and threatens native biological

diversity (Williamson 1996; IUCN, 2000;

Shine et al. 2000; McNeely et al. 2001).

Williamson (1996) has suggested the ‘‘three

tens rule’’:10% of imported species will be

introduced into new environments; 10% of

these will become established; 10% of these

will become invasives. The introduction of

exotic species is, arguably, a more significant

anthropogenic stressor than eutrophication or

toxic chemicals (Chapman, 1995) and, along

with habitat destruction, is the leading cause

of extinctions and resultant biodiversity

decreases worldwide. Thus the presence of

these exotics in Inland water bodies like

Vembanad integrates the issue as the native

fishes in the lake is facing threats from

various sources.

36

Chapter 5

Conservation Interventions

Fish Sanctuary in Kumarakam

The first engineered fish sanctuary was

constructed in Kumarakam by the Regional

Agricultural Research Station (RARS). A

circular area of 10ha was cordoned off by

planting coconut and bamboo piles at close

intervals to hinder fishing and obstruct

operation of crafts and gears. Since the

substratum at this location was muddy,

artificial sand hills were formed on the. A

variety of artificial ‘nest’ and ‘reef ’

substrates were deposited/ installed on the

lake floor to provide nesting surfaces for

pearlspots (Karimeen), as the fish is known to

attach their eggs on underwater substrates.

While developing this system, the habitat

requirements and spawning behavior of this

species were also taken in to consideration.

Half split coconut shells, large boulders of

laterite blocks, specially designed cement

concrete tetrapods and coconut piles were

used as ‘paaru’ and ‘reefs’ simulating

breeding habitats for fish, in the open lake

sanctuary. (Padmakumar et al 2001). The

success of this large scale fish sanctuary

rushed the government to sanction one more

fish sanctuary like this under the Kuttanad

package.

Lake protection forums and Fish

Sanctuary

As ATREE initiated, the fisher folk of

Vembanad is organized as Lake Protection

Forum (LPF). 14 units of LPFs are now

registered and are federated as Federation of

Lake Protection Forums. LPFs are now in the

forefront for organizing several conservation

programs at Vembanad.

MOne of the important activities of LPFs is

the Matsyathaavalam (fish sanctuaries).

Fishermen have created 6 small fish

sanctuaries (no fishing area with breeding

supports for fishes) based on their traditional

knowledge.

Traditionally ‘padal fishing’ was used as a

method to catch fish. Padals serves as a

spawning area and breeding platform for

many fishes and fish aggregate at such places.

But fishermen when use it as a method for

catching fish, it is a destructive practice, as

the catch will have more fingerlings and

brooders and hence considered as unethical

and ‘paddal fishing’ as such is banned. With

slight modification of this practice, fixing up

the paddals to serve as breeding ground with

the surrounding areas are protected , will

serve as a potential bio reserve.’. When

37

making such sanctuaries, protection and

management of the same was done by the

fishermen that has been proved as the best

practice for the revival of fish population. An

area of twenty cents was fenced in the 8 sites

in the Vembanad lake, using bamboo poles

with its branches. This is to hinder fishing and

obstruct operation of crafts and gears inside

this area. This is covered with nets to prevent

weeds flowing in to the area. Another core

area of 10 cents was fenced inside this 20

cents , again with bamboo poles and the reef

material was deposited in the core area. The

reef material was made of branches of locally

available trees such as cashew tree trunks etc.

The branches of the trees were cut in to piles,

each pile with 3 m length and 2 m breath and

1m height. About 50 such piles tied together

to form the reef mass, deposited inside the

inner fence, immersed in water and is fixed to

the poles in the fence. In addition to this some

mangrove will also be planted on the edges of

the sanctuary.

Matsyathavalam is periodically evaluated by

a professional team of experts from the

Aquaculture department of St,Albert’s college

, headed by Dr.Benno Perira. The experience

of the fishermen fishing in the lake closeby

areas and increased presence of otters and

cormonats nearby also certifies the success of

Matsyathavalam as a breeding haven for

fishes . . As recognition of the success of this

model in conserving the fishery, the Kerala

State Govt has come forward to support more

such sanctuaries through the Kuttanad

package.

Kuttanad Package

The Ministry of Agriculture, Government of

India approved special rehabilitation package

in 2004 for the farmers of 31 districts of

Andhra Pradesh, Karnataka, Kerala and

Maharashtra. Along with this the Government

approved a special plan of action for

improving farming conditions in Alappuzha

and Idukki districts of Kerala. The

Government requested M. S. Swaminathan

Research Foundation (MSSRF) to suggest

programmes for the strengthening the

ecological and livelihoods security of

Kuttanad wetlands in Alappuzha district with

the help of a multi-disciplinary team. The

study was directed to develop specific

recommendations on (1) Measures for

strengthening the ecological security of the

Kuttanad Wetland Ecosystem, and (2)

Measures for expanding sustainable

livelihood opportunities for the people of the

area.

Although the first and foremost

recommendations was to strengthen the

ecological security of the Kuttanad apart from

the modernization of Tannermukkam barrage

nothing much was mentioned in the report

38

that will help in the conservation the lake.

Many activities like strengthening the bunds

of the paddy fields with concrete slabs

affected adversely the ecology of the lake by

hindering the hiding and foraging places for

the aquatic fauna like shrimps and prawns.

The focus on fisheries and allied sectors was

minimal and the package fails to address

many issues of the fishermen like

deterioration of clam resources. The cluster

based cage culture mentioned by the package

ended up in a great failure as many cage

culture systems failed to work properly due to

lack of proper management and resulted in

large scale loss, especially in Muhamma

region. This failure of cage culture of pearl

spot caused the fishermen to culture Tilapia

in cages which is disputable.

39

Suggestions for Conservation of Vembanad Lake & Fishery Resources

1. Thanneermukkom Barrage is identified as a major threat to the ecosystem health and fish fauna of Vembanad. Hence the barrage should be kept open atleast for nine months to allow saline influx to the lake. To attain this, definite crop calendar should be followed in Kuttanad and paddy harvesting should be completed before March every year.

2. A comprehensive study on the ecological Impact of Thannermukkom barrage and its further development should be done by keeping the barrage experimentally open for atleast two years.

3. Any non-wetland use of the lake should be strictly regulated. 4. Increase awareness among fishermen in and around Vembanad on ethical fishing practices. 5. Fishery enhancement program adopted by the authorities should be done in accordance with

the fishermen and the suggestions by them should be incorporated in any such management plans.

6. Organic pollution from untreated sewage from the nearby towns and house boats and resorts are a major reason of concern. The government should take utmost care not to open any untreated sewage into the lake.

7. Strict measures should be adopted to prevent the deposition of plastic and other solid waste into the lake.

8. Ranching of exotic or transplanted fishes in Vembanad should be stopped as these can affect the diversity of native fishes.

9. Any developmental or modification works on critical fish habitats in vembanad lake should be done with proper impact assessment studies.

10. A democratic institution should be set up with ample representation for the traditional stakeholders and local panchayaths with due legal powers for the governance of the Vembanad lake and associated socio-ecological system.

40

References

A. Bijukumar, Krishnakumar K & Kurian Mathew Abraham( 2010) River Fish Monitoring

Programme:Manual of Methodology. Kerala State Biodiversity Board (KSBB), 32 pages

Abdul Aziz P.K and Nair, N.B., (1981). Certain aspects of pollution in the aquatic ecosystems of

the south-west coast of India. Proceedings of Seminar on Status of Environmental Studies in India:

pp 345 – 356

Chapman, P.M., (1995). Ecotoxicology and pollution–key issues. Mar. Pollut. Bull. 31, 167–177.

Gopalan, V. K., Doyil, T., Vengayil, P., Udayavarma, P. and Krishnankutty, M. (1983). The

shrinking backwaters of Kerala. J. Mar. Biol. Ass. India, 25: 131-141.

IUCN-The World Conservation Union.( 2000). IUCN Guidelines for the Prevention of

Biodiversity Loss due to Biological Invasion (Approved by the IUCN Council, February, 2000).

Knight J.D.M. ( 2010) On a record of Puntius gelius (Hamilton, 1822)

(Teleostei: Cypriniformes: Cyprinidae) from Tamil Nadu. Journal of Threatened Taxa 2(3): 786-

787.

Knight, J.D.M. & K.R. Devi (2010). Species persistence: a re-look at the freshwater fish fauna of

Chennai, India. Journal of Threatened Taxa 2(12): 1334-1337.

Krishnakumar, K., A. Ali, B. Pereira & R. Raghavan (2011). Unregulated aquaculture and

invasive alien species: a case study of the African Catfish Clarias gariepinus in Vembanad Lake

(Ramsar Wetland), Kerala, India. Journal of Threatened Taxa 3(5): 1737–1744.

Krishnakumar, K., R. Raghavan, G. Prasad, A. Bijukumar, M. Sekharan, B. Pereira & A. Ali

(2009). When pets become pests – exotic aquarium fishes and biological invasions in Kerala, India.

Current Science 97: 474-476

Kurup, B.M. & C.T. Samuel (1985). Fish and fishery resources of Vembanad Lake, pp. 77–82. In:

Ravindran, K., N.U. Nair, P.A. Perigreen, A.G.G. Pillai, P.A. Panicker & M. Thomas

(eds.). Harvest and Post- Harvest Technology of Fishes. Central Institute of Fisheries Technology

(CIFT) & Society of Fisheries Technologists (SOFTI), Kochi, India

41

Kurup, B.M., Sebastian, M.J. , Sankaran M.J. , and Rabindranatha. P. ( 1989) Exploited

fishery resource of vembanad lake. Final Report. Kuttanad Water Balance Study . p 142

McNeely J.A., Mooney H.A., Neville L.E., Schei P and Waage J.K. (eds)( 2001). A Global

Strategy on Invasive Alien Species Gland: IUCN Switzerland, and Cambridge UK, in Collaboration

with the Global Invasive Species Programme. X+50

Padmakumar K.G., Anuradha Krishnan, R.Radhika, P.S. Manu and C.K.Shiny (2001) Open

water fishery interventions in Kuttanad, Kerala, with reference to fishery decline and ecosystem

changes Riverine and Reservoir Fisheries, Challenges and strategies. Soc.Fish. Tech.(India), CIFT,

Cochin.pp.15-24.

Padmakumar K.G., L Bindu, Nitta Joseph, B.Sreekumar, G.Sunil, N.Unnikrishnan and

J.Sabu Kurien (2006). River Fish Inventory Under Participatory Approaches: ‘Meenachil Fish

Count 2004’.Environment and Ecology, 24S(3):584-590. 2006

Shine C., Williams N and Gundling L.( 2000). A Guide to Designing Legal and Institutional

Frameworks on Alien Invasive Species; IUCN, Gland, Switzerland Cambridge and Bonn. xvi+138

Williamson, M., (1996). Biological Invasions. Chapman & Hall, London

WWF (2002). Information sheet on Ramsar Wetlands (RIS). Accessed online on March 18

2010 http://www.wetlands.org/reports/ris/2IN019en.pdf.

42

Annexure

Check list of Fishes of VFC 2008-2011 with a Note on its Geographical Distribution

Main reference used Catalog of Fishes (http://research.calacademy.org/redirect?url=http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp)

Family: CLUPEIDAE

1. Dayella malabarica (Day 1873).

Distribution: Western Indian Ocean, southwestern India.

Family CYPRINIDAE

2.Amblypharyngodon melettinus (Valenciennes 1844)

Distribution India and srilanka

3. Amblypharyngodon mola (Hamilton 1822).

Distribution: Asia: Pakistan, India, Sri Lanka, Nepal and Bangladesh.

4. Catla catla (Hamilton 1822).

Distribution: Nepal, India, Bangladesh and Pakistan.

5. Laubuca dadiburjori (Menon 1952)

Distribution: India.

6. Labeo dussumieri (Valenciennes 1842).

Distribution: India and Sri Lanka.

7. Labeo rohita (Hamilton 1822).

Distribution: Asia: India, Pakistan, Nepal, Sri Lanka; introduced widely in Asia

8. Puntius amphibious (Valenciennes 1842).

Distribution: India.

9. Puntius filamentosus (Valenciennes 1844)

Distribution: India.

10. Puntius mahecola (Valenciennes 1844).

43

Distribution: Kerala, southern India.

11. Puntius sarana (Hamilton 1822).

Distribution: Asia: Nepal, India, Myanmar, Pakistan, Bangladesh and Sri Lanka.

12. Puntius subnasutus (Valenciennes 1842)

Distribution India

Currently designated as a junior synonym of Puntius sarana (Hamilton 1822).

13. Puntius ticto (Hamilton 1822).

Distribution: Asia: Pakistan, India, Sri Lanka, Nepal, Bangladesh and Myanmar.

14. Puntius vittatus (Day 1865)

Distribution: Asia: Pakistan, India and Sri Lanka

15. Rasbora daniconius (Hamilton 1822).

Distribution: Asia: Nepal, India, Sri Lanka, Laos, Thailand, Malaysia, Bangladesh, Pakistan and Myanmar.

Family: ARIIDAE

16. Arius maculatus (Thunberg 1792).

Distribution: Northern Indian Ocean and western Pacific/South and southeast Asia: Sri Lanka, Thailand, Indonesia, Philippines and China.

17. Arius subrostratus (Valenciennes 1840)

Distribution: South and southeast Asia: Pakistan, India, Sri Lanka, Thailand, Singapore, Indonesia and Philippines. Habitat: brackish, marine.

Family: BAGRIDAE

18. Mystus armatus (Day 1865).

Distribution: Southern central Asia: India, Bangladesh, Myanmar, Pakistan (?).

19. Mystus gulio (Hamilton 1822).

Distribution: Pakistan, India, Bangladesh, Sri Lanka, Myanmar, Thailand, Malaysia and Indonesia.

44

20. Mystus vittatus (Bloch 1794).

Distribution: Southern central Asia: Pakistan, India, Nepal, Sri Lanka and Bangladesh.

21. Horabagrus brachysoma (Günther 1864).

Distribution: Southern and southeastern Asia.

Family: SILURIDAE

22. Wallago attu (Bloch & Schneider 1801).

Distribution: South central and southeastern Asia: Pakistan, India, Sri Lanka, Nepal, Bangladesh, Myanmar, Thailand, Indonesia and East Indies.

23. Ompok malabaricus (Valenciennes 1840).

Distribution: India.

Family: PANGASIIDAE

24. Pangasianodon hypophthalmus (Sauvage 1878).

Distribution: Mekong, its basin, and Chao Phraya, Thailand; introduced elsewhere in Asia

Family: HETEROPNEUSTIDAE

25. Heteropneustes fossilis (Bloch 1794).

Distribution: Southern Asia: Iran (introduced), Iraq (introduced), Pakistan, India, Sri Lanka, Nepal, Bangladesh, Myanmar, Thailand and Laos.

Family: LORICARIIDAE

26. Pterygoplichthys multiradiatus (Hancock 1828).

Distribution: Orinoco River basin, Guyana (?) and Venezuela; Argentina (?); introduced elsewhere, including Taiwan, Hawaiian Islands and Florida..

Family : APLOCHEILIDAE

45

27. Aplocheilus lineatus (Valenciennes 1846).

Distribution: India and Sri Lanka.

28. Aplocheilus panchax (Hamilton 1822).

Distribution: Asia: Pakistan, India, Nepal, Bangladesh, Myanmar, Malaysia, Indonesia and Thailand.

Family : AMBASSIDAE

29. Ambassis ambassis (Lacepède, 1802)

Distribution Western Indian Ocean: East Africa and South Africa east to Madagascar, Réunion and Mauritius

30. Parambassis dayi (Bleeker 1874).

Distribution: India

31. Pseudambassis ranga (Hamilton 1822).

Distribution: Asia: Pakistan, India, Nepal, Bangladesh, Myanmar and Malaysia. Habitat: freshwater, brackish.

32. Parambassis thomassi (Day 1870).

Distribution: India

Family: SCATOPHAGIDAE

33. Scatophagus argus (Linnaeus 1766).

Distribution: Indo-West Pacific: India and Sri Lanka east to Society Islands (French Polynesia), north to southern Japan.

Family CARANGIDAE

34. Alepes djedaba (Forsskål 1775)

Distribution: Red Sea, Indo-West Pacific: East Africa east to Hawaiian Islands, north to southern Japan, south to northern Australia; Mediterranean Sea (Red Sea immigrant).

35. Carangoides malabaricus (Bloch & Schneider 1801).

46

Distribution: Red Sea, Indo-West Pacific: East and South Africa and Madagascar east to Philippines and New Guinea, north to southern Japan, south to Exmouth Gulf (Western Australia) and New South Wales (Australia) at 33°00’S.

Family:LEIOGNATHIDAE

36. Eubleekeria splendens (Cuvier 1829).

Distribution: Red Sea, Indo-West Pacific: East Africa, Madagascar and Mascarenes east to Philippines and Fiji, north to Ryukyu Islands and Taiwan, south to Kimberleys (Western Australia), Queensland (Australia) and New Caledonia.

37. Photopectoralis bindus (Valenciennes 1835).

Distribution: Red Sea, Indo-West Pacific: Gulf of Aden east to Philippines and Fiji, north to Taiwan, south to Western Australia and New Caledonia.

Family: GERREIDAE

38. Gerres filamentosus Cuvier 1829.

Distribution: Red Sea, Indo-West Pacific: East Africa, Madagascar and western Mascarenes east to Fiji, north to southern Japan, south to Western Australia, Queensland (Australia).

39. Gerres setifer (Hamilton 1822).

Distribution: Northeastern Indian Ocean: Bay of Bengal and Andaman Sea.

Family: SIGANIDAE

40. Siganus javus (Linnaeus 1766).

Distribution: Indo-West Pacific.

Family : ENGRAULIDAE

41. Stolephorus indicus (van Hasselt 1823).

Distribution: Red Sea, Indo-West Pacific: East and South Africa east to Caroline, Mariana and Society islands, north to South China Sea, southeard to Dampier Archipelago (Western Australia), Queensland (Australia) and New Caledonia

47

Family: SCIAENIDAE

42. Johnius dussumieri (Cuvier 1830).

Distribution: Indian Ocean.

Family: LATIDAE

43. Lates calcarifer (Bloch 1790).

Distribution: Indo-West Pacific: Asian Coast and Indo-Australian Archipelago; mostly in brackish and fresh water.

Family: NANDIDAE

44. Nandus nandus (Hamilton 1822).

Distribution: Southern Asia: Pakistan, India, Nepal, Bangladesh, Myanmar, Thailand and Malaysia.

45. Pristolepis rubripinnis ( Britz, Krishnakumar and Fibin baby 2012)

Distribution: Kerala, South of Palaghat Gap

Family: CICHLIDAE

46. Etroplus maculatus (Bloch 1795).

Distribution: India and Sri Lanka.

47. Etroplus suratensis (Bloch 1790).

Distribution: India and Sri Lanka.

48. Oreochromis mossambicus (Peters 1852).

Distribution: Southeastern Africa; introduced widely elsewhere.

Family : MUGILIDAE.

49. Mugil cephalus (Linnaeus 1758)

48

Distribution: Nearly circumglobal in temperate and tropical seas and estuaries (including Mediterranean Sea, Black Sea, Red Sea and Hawaiian Islands); apparently not in the western Atlantic [ref. 30860]; introduced in some lakes

Family CHANIDAE

50. Chanos chanos (Forsskål 1775).

Distribution: Red Sea, Indo-Pacific and adjacent river systems: East Africa, South Africa, Seychelles, Madagascar and Mascarenes east to Hawaiian Islands and Panama, north to southern Japan, south to Western Australia at 32°05'S, New South Wales (Australia) and Norfolk Island. Mediterraanean Sea immigrant.

Family : GOBIIDAE

51. Glossogobius giuris (Hamilton 1822).

Distribution: Southern Red Sea, Indo-West Pacific: East Africa, South Africa, Seychelles, Madagascar and western Mascarenes east to Society Islands, north to Philippines, south to Western Australia, New South Wales (Australia) and New Caledonia.

Family ELEOTRIDAE

52. Butis butis (Hamilton 1822).

Distribution: Indo-West Pacific: East Africa, South Africa, Seychelles and western Mascarenes east to New Guinea, north to South China Sea, south to northern Australia.

Family ANABANTIDAE

53. Anabas testudineus (Bloch 1792)

Distribution: Indo-West Pacific [native to southeastern Asia from India to Sri Lanka to Indonesia, Philippines and China]; introduced widely elsewhere.

Family: OSPHRONEMIDAE

54. Pseudosphromenus cupanus (Cuvier 1831).

49

Distribution: India, Sri Lanka and Bangladesh.

55. Pseudosphromenus dayi (Köhler 1908).

Distribution: India.

Family : CHANNIDAE

56. Channa marulius(Hamilton 1822).

Distribution: Southern and southeastern Asia: Pakistan to southern China, Thailand, Laos and Vietnam; introduced elsewhere, including southern Florida.

57. Channa gachua (Hamilton 1822).

Distribution: Southern and southeastern Asia: Afganistan and Iran to China and Malaysia and Indonesia.

58.Channa striata (Bloch 1793).

Distribution: Southern Asia: Native range Pakistan to China, Thailand, Malayasia and Indonesia; introduced elsewhere.

Family: MASTACEMBELIDAE

59. Mastacembelus armatus (Lacepède 1800).

. Distribution: Pakistan to China, Taiwan and southeastern Asia.

Family SOLEIDAE

60. Brachirus orientalis (Bloch & Schneider 1801).

Distribution: Red Sea, Indo-West Pacific: Madagascar and Persian Gulf east to Philippines, north to Taiwan, south to northern Australia. Habitat: brackish, marine.

Family: CYNOGLOSSIDAE

61. Cynoglossus macrostomus (Norman 1928).

Distribution: Northern Indian Ocean.

50

Family: TETRAODONTIDAE

62. Carinotetraodon travancoricus (Hora & Nair 1941).

Distribution: India. Habitat: freshwater.

63. Chelonodon patoca (Hamilton 1822).

Distribution: Indo-West Pacific: India and Sri Lanka east to French Polynesia, north to southern Japan, south to northern Australia.

Family BALISTIDAE

64. Balistes capriscus (Gmelin 1789.)

Distribution: Mediterranean Sea, Black Sea, Atlantic.

Family : HEMIRAMPHIDAE

65. Hyporhamphus limbatus (Valenciennes 1847).

Distribution: Persian Gulf to China along the mainland of Asia: Nepal, India, Bangladesh, Myamar.

66. Hyporhamphus xanthopterus (Valenciennes 1847).

Distribution: Eastern Indian Ocean, western Pacific, Asia: India to Thailand and adjacent marine waters.

Family: BELONIDAE

67. Xenentodon cancila (Hamilton 1822).

Distribution: Asia: Pakistan, India, Sri Lanka, Bangladesh, Myanmar, Malaysia and Thailand; introduced elsewhere including Hawaiian Islands